/**
 * Copyright 2010-2012 initialize4j.org
 *
 * <pre>
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 * </pre>
 */
package org.initialize4j.service;

import java.lang.reflect.Field;

import org.initialize4j.Initialize;
import org.initialize4j.util.InitializationUtil;

import com.google.common.base.Predicate;

/**
 * A PreconditionInspector inspects that some mandatory precondition for
 * initializing are given.
 * 
 * @author <a href="hillger.t@gmail.com">hillger.t</a>
 */
final class InitializePreconditionInspector {

	/**
	 * Returns true if some defined precondition for an annotated field is
	 * satisfied.
	 * 
	 * @param value The value to inspect.
	 * @param field The field to inspect.
	 * @return True if the condition is satisfied - false otherwise.
	 * @throws InitializeException
	 */
	boolean isPreconditionSatified(Object value, Field field) {
		if (field.isAnnotationPresent(Initialize.class)) {
			Initialize initialize = field.getAnnotation(Initialize.class);
			
			@SuppressWarnings("unchecked")
			Predicate<Object> satify = (Predicate<Object>) InitializationUtil.instance(initialize.when());
			return satify.apply(value);
		}
		return false;
	}
}
